Magnetic starter switch



1957 c. c. PALMER EIAL MAGNETIC STARTER SWITCH 2 Sheets-Sheet 2 Filed Oct. 22, 1955 INVENTORS. ADELBERT BAR/PX BY CARL c. PALMER,

Ar'mR/VEX MAGNETIC STARTER SWITCH Appiication October 22, 1953, Serial No. 387,756

4 Claims. (Cl. 200-87) This invention relates to a magnetic starter switch particularly designed for use in well logging operations. In such operations it is desirable to have an automatic starter switch to initiate the operation of the electronic equipment contained within a logging probe when the probe has arrived at the lower end of the drill stem, or at any other desired location in the stem. In the past, magnetic apparatus have been used. However, magnetic apparatus heretofore known to the art have proved to be inefficient in that they are often accidentally tripped before the instrument is located in the proper position. An object of this invention is to provide a magnetic starter switch which will not operate unless properly positioned in the desired location within the drill stem.

A further object of this invention is to devise a starter switch which will not be actuated while being transported to and from the well, due to vibrations such as the movement of a truck carrying the equipment in which the starter switch is contained.

This invention achieves the aforementioned objects by the provision of a plurality of independently movable bar magnets. These independently movable bar magnets are moved outwardly when influenced by an outside force such as a magnetic field. The bar magnets are also infiuenced by gravity. In the drill stem at any desired location the inside diameter is reduced, said diameter being large enough to permit the instrument in which the magnetic switch is contained to position itself on the shoultiers of the reduced portion. The drill stem being made or magnetic material and having a magnetic field attracts the plurality of bar magnets outwardly thereby causing L the electrical switches contained within the instrument to be actuated. It can be seen that until the magnetic starter switch reaches the desired location within the stem the switch will not be actuated and upon withdrawal of the instrument from said location, operation of the instrument is automatically terminated.

When the instrument is in a horizontal position one of said plurality of bar magnets will rest against the side of the instrument casing. The other bar magnet will incline toward the axis of the instrument casing. In order for the switches to be actuated it is necessary that all of said plurality of bar magnets be moved outwardly from the axis of the instrument casing. Hence when the instrument is in a horizontal position it is impossible for the electrical switches to be actuated due to vibration or any other outside influence.

in the drawings Fig. l is an elevational view of the magnetic starter switch mounted within a nonmagnetic section of a well instrument.

Fig. 2 is a side view partly in section taken at right angles to Fig. 1;

Fig. 3 is a front elevational view similar to Fig. 1 but with the parts in operating position due to the proximity of ferromagnetic material such as a core bit seat in a drill bit; and

Fig. 4 is a front elevational view illustrating the posiited States Patent tion of the parts when the instrument is in a horizontal position for transport.

Referring now to the drawings, the magnetic starter switch is located in a nonmagnetic casing 1. This casing has a pair of inturned sections 16 to provide a seat for a base 3. The base is screwed onto the inturned sections by means of screws 17. Base member 3 has integral therewith a pair of support plates 8, said support plates providing a hollow column into which a rocker plate 7 may be inserted. Also pivotally connected to the base 3 are a plurality of brackets 5. These brackets have upturned fingers 6 adapted to move the rocker plate 7 when the bar magnets 4 which are situated on the brackets are moved outwardly. Also connected to said base 3 is a frame 2. The top portion of the frame member 2 has integrally attached thereto a shading bar 14, the purpose of which will be explained later. By means of a pair of books a tension spring 9 is attached at one end to the base member 3 and at the other end to the rocker plate 7. The tension of the spring serves to maintain the rocker plate 7 in a downward position unless moved upwardly by outward movement of the bar magnets 4. The rocker plate 7 can be pivotally and slidably moved within slots 18 in the support plates 8. Located on the rocker plate are a plurality of electrical contacts 10 insulated from the rocker plate by means of insulating material 11. A plurality of fixed contacts 12 are mounted on either side of column 8 and insulated therefrom by insulators 13. In order for the electrical system to be actuated, thereby sending current to the electronic equipment contained within the drill stem, it is absolutely necessary that each electrical contact 10 engage two oppositely opposed fixed electrical contacts 12. The magnetic bars create in shading bar 14 by induction a magnetic pole of opposite magnetic polarity to the polarity of the upper section of the magnetic bars 4. Hence a slight attractive force exists between the shading bar 14 and the plurality of bar magnets 4. The mass of the shading bar determines the magnitude of said magnetic force. By selection of the mass of bar 14, the upper poles of magnets 4-4 are sufficiently attracted to maintain the magnets normally in the positions of Fig. 1, but not attracted to such a degree as to prevent the magnets from being attracted by a larger mass external of housing 1. Stop screws 15-15 limit the inward movement of magnets 4-4 upon their pivots and prevent the magnets from sticking to the shading bar. The tension of the spring member 9 is just sufiiciently to maintain the rocker plate 7 snug against the lower portion of the slot member 18. It is so provided because it is desirable to have the rocker plate moved upwardly or pivotally upon the slightest contact of the fingers 6 against the rocker plate 7. The tension spring 9 is not utilized to maintain the bar magnets 4 in an inwardly inclined position. It is for maintaining the magnets 4 inclined inwardly that the shading bar 14 is used. The strength of spring 9 necessary to maintain the magnets 4 inclining inwardly would lessen the instruments sensitivity to external magnetic material.

In Fig. 3 the instrument in which the magnetic starter switch is contained is shown seated within the smaller diameter portion of the drill bit. As is shown, the magnetic bar magnets have been moved outwardly due to the magnetic field of the drill bit. The bar magnets have also slidably moved rocker arm 7 and its contacts 10 into engagement with contacts 12 to thereby actuate the electronic equipment contained within the drill stem.

In Fig. 4 our new magnetic starter switch is shown when the instrument casing is in a horizontal position. When in said horizontal position the bar magnet closer to the surface of the earth rests against the inside surface of the instrument casing due to the influence of gravity.

The bar magnet located on the other side of the axis of the casing is moved downwardly toward the axis of said casing and is limited in movement by means of a set screw 15.

In operation, the instrument containing the new magnetic starter switch is lowered into the drill stem. The strength of the magnets and the proportions of the instrument are such that the magnets will not be drawn outwardly when the instrument is centered within the drill stem. It can be readily appreciated the magnetic starter switch will not be actuated until it is positioned in the desired section of the drill stern. If in passing from the top of the borehole to the desired location in the drill stem the instrument containing the magnetic starter switch should deviate from the center of the drill stern enough to come under the influence of the magnetic material of which the drill stem is made only one of the bar magnets will be moved outwardly. The remaining magnets will be maintained in their inwardly inclined position because of the increased separation between them and the drill stem wall. Since it is necessary that all the bar magnets be moved outwardly to actuate the electrical contacts the magnetic switch will not be unintentionally actuated. The switch is also housed within a cut in portion of the casing 1. This arrangement prevents the magnets from getting too close to the drill stem wall.

While a preferred embodiment of our invention has been describedit will be understood that our invention may Well take other forms and it is intended, therefore,

to cover in the appended claims all such changes and modifications as fall within the true spirit and scope of our invention. Other arrangements such as for moving mechanical linkages, starting clock Works, etc. may be attained without departing from the spirit of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In a magnetic starter switch for use in a magnetic drill stem, a nonmagnetic casing, a base positioned within said casing, two spaced plates integral with said base, a plurality of brackets having upwardly turned fingers adapted to engage a rocker plate, said plurality of brackets being pivotally connected to said base, a bar magnet adapted to engage said rocker plate positioned on each of said plurality of brackets, a frame connected to said base with its top portion being vertically spaced from said base, a shading bar attached to said top portion, said shading bar being polarized in such a manner as to attract the bar magnets, a tension spring one end of which is connected to said base along the axis thereof, the other end being connected to said rocker plate, said rocker plate being pivotally and slidably mounted between said two spaced plates, a plurality of fixed electrical contacts positioned on said plates and vertically spaced from said rocker plate, and a plurality of contact bars on said rocker plate, said contact bars being adapted to engage said fixed electrical contacts upon movement of said rocker plate in opposition to the force of said tension spring, upon movement of all said bar magnets.

2. In a magnetic starter switch for use in a magnetic drill stem, a casing, a base mounted Within said casing, a support integral with said base, a plurality of brackets having upwardly turned fingers adapted to engage a rocker plate, said plurality of brackets being pivotally connected to said base, an independently movable magnet positioned on each of said plurality of brackets, resilient means connected to said base and to said rocker plate, said rocker plate being pivotally and slidably mounted on said support, said rocker plate having pivotal motion upon the outward movement of some of said independently movable magnets and sliding motion upon the substantially simultaneous outward movement of all said magnets.

3. A magnetic switch comprising a base, a plurality of means each independently movable in response to a magnetic field attached to said base, a plurality of first contact means fixedly connected to said base, second contact means movably mounted on said base adapted to contact said first contact means upon movement thereof, said first and second contact means being adapted to complete an electrical circuit when said second contact means is in contact with all of said plurality of first contact means, said second contact means being connected to and movable in response to movement of said magnetic field responsive means, said second contact means contacting said plurality of said first contact means to complete said electrical circuit upon substantially simultaneous movement of said plurality of magnetic field responsive means.

4. A magnetic switch comprising a base, a plurality of magnets each independently movable in response to a magnetic field attached to said base, a plurality of first contact means fixedly connected to said base, second contact means movably mounted on said base adapted to contact said first contact means upon movement thereof, said first and second contact means being adapted to completean electrical circuit when said second contact means is in contact with all of said plurality of fixed contact means, said second contact means being connected to and movable in response to movement of said magnets, said second contact means contacting said plurality of first contact means to complete said electrical circuit upon substantially simultaneous movement of said magnets.

References Cited in the file of this patent UNITED STATES PATENTS 586,920 Wellman July 20, 1897 773,324 Hopewell Oct. 25, 1904 FOREIGN PATENTS 338,046 Great Britain Nov. 13, 1930 559,453 Great Britain Feb. 21, 1944 

